Problem: Shreya has $40$ pairs of shoes stacked in boxes. If a pair is $2$ shoes, how many shoes does Shreya have?
Answer: ${40}$ boxes is the same as ${4\text{ groups of ten}}$ boxes. There are $2$ shoes in each box. Total number of shoes: $\begin{aligned}&2\times{4\text{ groups of ten}}\\ =&{8\text{ groups of ten}}\\ =&{80}\end{aligned}$ Shreya has ${80}$ shoes.